Almost one in 10 GCSE entrants have achieved top grades in Northern Ireland.
Rising numbers earned grades C or better and the proportion receiving A* increased by 0.1% to 9%.
Levels of performance in English and maths continued to rise - boys showed notable improvement - but girls were still ahead, exams body the Joint Council for Qualifications (JCQ) said.
The proportion of entries in Stem subjects (science, technology, engineering and mathematics) has grown by 3%.
The tally of entrants awarded A*-C grades has risen by 0.7 percentage points to 78.7%. Entries achieving A* - A have improved 0.4 percentage points to 28.6%, and the number achieving the top A* grade now sits at 9%, a slight rise of 0.1 percentage points on last year.
This year performance in mathematics improved with 66.6% of entries awarded A*-C, up 0.4 percentage points on 2014. Levels of achievement in English also improved with A*-C grades now representing 75.8% of entries in the subject, a rise of 2.8 percentage points.
The percentage of male entries achieving A*-C rose a full percentage point in 2015 to 75.1%. However, girls are still well ahead in GCSE performance, with 82.2% of all female entries gaining the A*-C grades, up 0.5 percentage points on last year.
Justin Edwards, chief executive of Northern Ireland’s awarding organisation, the Council for the Curriculum, Examinations and Assessment (CCEA), said: “This year’s results show a steady improvement in A*-C grades. Importantly the grades in English and mathematics have continued to build on the good performance of recent years.
“The general pattern of growth in Stem subjects that emerged last week at A level is repeated in today’s GCSE figures. This is underpinned by notable growth in mathematics and ICT.
“It’s also encouraging to see the improved performance of males this year, closing the gender gap at grades A*-C.”